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( M del.) 2 Sheets$heet 1. P. G. CHAPMAN 8v I. M. BEARING.

ARC LAME.

No, 414,141. Patented Oct. 29, 1889.

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ARC LAMP.

Patented Oct. 29, 1889.

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UNITED STATES PATENT OEEIcE.

EREDERIO GEORGE CHAPMAN AND ERED MlTCIlELL BEARING, OF LONDON, ENGLAND,ASSIGNORS OF ONE-THIRD TO \VILLIAM GEORGE CHAPMAN,

OF SAM E PLACE.

ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 114,1 11, dated October29, 1889.

Application filed $eptember 27,1888. Serial No. 286,497. (No model.)Patented in England May 13, 1887, No. 7,0 i2; in France March 18, 1888,No. 189,332; in Belgium March 13, 1888, No. 81,012, and in GermanyApril, 1888, No. 46,725.

To all whom it 71mg concern.-

Be it known that we, EREDERIC GEORGE CHAPMAN and FRED MITCHELL DEARING,both residents of London, England, and sub- 5 jects of the Queen ofGreat Britain, have invented an Improvement in Electric-Arc Lamps,(patented to ourselves and \V. G. Chapman in England under date ofMay13, 188?,No. 7,012; in France March 13, 1888, No.

Io 189,332; in Belgium March 13, 1888, No. 81,012, and in Germany Aprilat, 1888, No. 46,725,) of which the following is a specification.

Our invention relates to electric-arc lamps.

Its objects are to give a better distribution of light horizontally anddownward by a peculiar shape of the arc, and at the same time to afforda steady light with a fixed position of are, so as to facilitate exactfocusing in searchlights and the like, and to render the life orduration of the positive and negative carbons equal or substantiallyequal, also to offer less resistance to the current within the lamp andto afford more reliable self-acting provisions for feeding and adjustingthe respective carbons. To effect these objects we construct our lamp asfollows, and in order that our invention may be the better understood We110w proceed to describe the same in relation to the drawings hereuntoannexed, reference being had to the letters and figures marked thereon.

Like letters refer to like parts in the several figures.

Figure 1 represents a general elevation of our improved lamp. Fig. 2represents a longitudinal section and a cross-section of one of thepositive guiding-tubes. Fig. 3 is an elevation and plan of theretaining-collar of the negative guiding-tube.

A A represent the positive carbon divided into two parts meeting abovethe negative pole and arranged horizontally.

13 is the negative carbon, placed vertically and underneath the point ofcontact of the two positive carbons, so that the poles meet one anotherat right angles in the form of a letter T. The current introduced at thebinding-screws C, Fig. 1, passes round one part of the solenoid l), andthence is divided in parallel either by suitable wires or by thestandards Z) I) to the two parts of the horizontal poles, respectively,and thence to the negative carbon 13, thus forming the electric arebetween their respective points. The current returns from the negativepole through the mercury contacts E and the insulated fra1ning F to thebinding-screw G. As a consequence of this arrangement of poles, apeculiarly-shaped crater a is formed on the under side of the center ofthe positive pole, where the two ends of the parts join. This causes afan-shaped are exceptionally eifective for the distribution of light.horizontally and downward in adit'fused manner and to a much greaterextent than in the ordinary arrangement of vertical poles. The positionof the arc, by reason of the character of the feed of the'negative polebeing always toward the fixed position of the positive pole, remains 7calways in an absolutely fixed position, which is of great value wherethe light has to be focused or reflected. Moreover, as the ratio of therate of burning of the positive carbon to that of the negative carbon isas two to one about, it follows that with carbons of a given length oneset of the positive carbons will just last out the single negativecarbon, which prevents waste and materially simplifies renewin thecarbons. 30

The two parts of the positive pole A A are fed together by the pressureof a spring conveniently coiled in the drum H, the cords h h being takenfrom the periphery of the said spring-drum and attached to pins 0 c,which are inserted into metallic plugs (Z (I, traveling in the metalguiding-tubes K K. The points of the plugs (Z (Z are wedge-shaped andpress into suitable recesses in the rear of the positive carbons A A,and prevent the latter from turning on their axes. The guidingtubes Kare slotted, so as to permit the pins 0 c to travel along the said tube,and thus transmit the pressure of the spring-drum H by the metallicplugs (Z (Z to feed home the 9 two positive carbons A A, so that theirextremities always remain in contact with one another. o mayequivalently operate the automatic feed of these positive carbons by a-Weight or weights or other similarly-applied spring-pressure. Thesecarbons are provided at top with a groove g, Fig. 2, which isadvantageous in preventing an obstructive skin on the positive carbonsabove the crater, and thus adapting them to feed easily and so as tomaintain the required shape of crater. Rollers f f k is press on theupper and under sides of the carbons, providing smoother travel to thecarbons, and one pairk is is fitted with springs pressing upon thecarbons, which helps to insure exceptionally tional area, so as toenable us conveniently to use lamps of great power and to providecarbons with the least possible resistance. The lower negative carbon Bis also selffed conveniently by the pressure of the spring g within themetallic holding-tube L. The said metallic holding-tube L is providedwith a retaining collar or device M, of which we find the mostconvenient form is provided with a pair of end extensions, as shown, inwhich small metallic strips m m, passing through holes in the said endextensions of the retainin g-collar M, are readily adjusted and securedby screws ll, workin gin slots in the said strips, so that they can bepushed forward to press against the end of the negative carbon, as maybe found desirable, and are readily replaced when burned or worn. Thespiral spring 9 presses the negative carbon B as it consumes always homeagainst this retaining device, similarly to the action of a self-feedcandle; or we may adopt any other equivalent arrangement.

The regulation for making and breaking the arc and for the adjusting ofthe same as to distance is eifected by the solenoid D D, Fig. 1, part ofwhich D is wound in series in the main current, and the other part D iswound in a shunt-circuit therefrom. The diiferential action is therebyobtained upon the solenoid-core for any changes in the re sistance ofthe main circuit by break in the light or by variations in the distanceof the poles from one another. The movement of the core N of the saidsolenoid is communicated by the bell-crank lever P, the vertical rod 10,and the rocking arm Q to the vertically-inovin g negative-pole tube L.The bell- 'conducting coupling q.

crank P is provided with a balance-weight n, and the vertical rod 12 isinsulated by a non- (Shown by an appended section in Fig. 1.)-

In order to insure reliableelectric contact between thevertically-moving negative-pole tube and the fixed frame F, through oralong which the current is conducted to the said pole, we provide amercury-cup B, Fig. 1, with metallic wire r therein of sufficient lengthto permit of the necessary vertical movement of the said tube withoutbreak of metallic contact. We apply also a piston 8, attached to thevertical rod 10, working in a cup of oil T, to act as a dash-pot tocontrol any sudden movement of the regulating device. We may use adeflector or protector V, of kaolin, asbestus, or other refractorysubstance, above the arc to protect the upper framing and parts from theheat of the arc.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the sameis to be performed, we declare thatwhat we claim is- 1. In combination with a vertical negative carbon, itsguide and feeding and adjusting devices, a two-part positive carbonprovided wit-h notches in its outer ends, tubular horizontal guides forthe same, each provided near the arc position with a pair ofcontactrollers, one of which is spring-pressed, plugs working in saidguides having wedge-shaped ends fitted to said notches, a feed-drum andconnections, and conducting-supports for said guides, substantially asdescribed.

2. In combination with 'a vertical negative carbon, its guide andfeeding and adj usting devices, the two-part cylindrical positive carbonhaving a skin-preventing groove along its top and provided with notchesin itsouter ends, andtubular horizontal guides for the same extendinglaterally from points near FREDERIO GEORGE CHAPMAN. FRED MITCHELLDEARING.

Witnesses:

RICHARD A. HOFFMANN, SAM P. WILDING.

